This invention relates in general to electronic instrumentation systems wherein computer-based instrument modules installed in a chassis communicate with a host computer through backplane wiring on the chassis, and more particularly to a development system for such instrument modules.
When an electronic equipment test, computation or control function involves the use of more than one instrument, difficulties arise in coordinating their operation. U.S. Pat. No. 4,707,834, entitled "Computer-based Instrument System" issued Nov. 17, 1987 to Frisch et al, describes a system for interconnecting several instruments to a host computer. Cards installed in slots of an equipment chassis form various instruments that communicate with one another and with an external host computer through a system bus on the equipment chassis. Each instrument board suitably includes a microcomputer that communicates with the host computer via one of the busses and controls instrument operation in response to instructions from the host computer. Other backplane busses interconnecting the instrument boards eliminate the need for custom wiring by conveying control and data signals between the various instruments. A similar system is under consideration by the Institute of Electrical and Electronics Engineers as standard for an open architecture modular instrument system called the "VXIbus", an extension of IEEE standard 1014 computer bus, also known as the "VMEbus".
While the VXIbus system helps an instrument user to automate tests involving several instruments, it complicates the job of an instrument maker. The instrument maker not only must design and build an instrument to carry out some particular function, but must also design the physical layout of the instrument to fit within one or more VXIbus slots and must develop computer-based hardware and firmware appropriately interfacing the instrument to the VXIbus. The time and cost of developing the interface circuits and firmware controlling it can be high, particularly to an instrument maker not having extensive experience in computer hardware and firmware design.